Re: Error while plotting NCEP data

Hi A.R.,
Also, you might want to check to make sure that your data is of type
float, and not of type short. In my NCEP Reanalysis holdings, uwnd/vwnd
data is of type short. (Add a printVarSummary(U) line in after you read
in the variable to check.) If the data is of type short, use short2flt
to convert it to floats:
http://www.ncl.ucar.edu/Document/Functions/Contributed/short2flt.shtml
Adam

On 03/08/2010 09:07 AM, Mary Haley wrote:
> A.R.
>
> With an error like this, it helps to debug it by turning off some of
> your resources. Perhaps
> you have them set to values that are not in the range of your data.
>
> I would start by commenting out these three lines, and see what you get
> by default, and
> also see if you still get the error message:
>
>> res@vcRefMagnitudeF = 5.0 ; make vectors larger
>> res@vcRefLengthF = 0.005 ; ref vec length
>> res@vcMinDistanceF = 0.017 ; thin out windbarbs
>
> If you don't get an error message, then look at the plot to see
> what the default reference vector is, and use this information
> to help determine if the one you picked was too large.
>
> --Mary
>
>
> On Mar 8, 2010, at 1:12 AM, A.R Ragi wrote:
>
>> Dear NCl users..,
>> I'm getting error while coding wind vectors using NCEP data.
>> I'm attaching the code.
>>
>>
>>
>> begin
>>
>> u = addfile("/CMAP/WIND/uwnd.mon.mean.nc <http://uwnd.mon.mean.nc>","r")
>> v = addfile("/CMAP/WIND/vwnd.mon.mean.nc <http://vwnd.mon.mean.nc>","r")
>>
>> U = u->uwnd(:,:,:,:)
>> V = v->vwnd(:,:,:,:)
>>
>> wks = gsn_open_wks("ps","windpattern_cmap") ; open ps file
>>
>> gsn_define_colormap(wks,"BlAqGrYeOrReVi200") ; choose color map
>> i = NhlNewColor(wks,0.8,0.8,0.8) ; add gray to colors
>>
>> res = True ; plot mods desired
>> res@gsnSpreadColors = True ; use full colormap
>> res@gsnSpreadColorEnd = -2 ; don't use added gray
>> res@lbOrientation = "vertical" ; vertical label bar
>>
>> res@tiMainString = "Windpattern"
>>
>>
>> res@vcRefMagnitudeF = 5.0 ; make vectors larger
>> res@vcRefLengthF = 0.005 ; ref vec length
>> res@vcMinDistanceF = 0.017 ; thin out windbarbs
>> res@vcGlyphStyle = "WindBarb" ; choose wind barbs
>> res@vcMonoWindBarbColor = False ; color barbs by scalar
>> res@vcWindBarbTickLengthF = 0.3 ; length of the barb tick
>> res@vcWindBarbTickSpacingF = 0.3 ; distance between ticks
>>
>>
>> ; zoom in on map
>>
>> minlat = -20
>> maxlat = 40
>> minlon = 40
>> maxlon = 120
>>
>> res@mpMinLatF = minlat
>> res@mpMaxLatF = maxlat
>> res@mpMinLonF = minlon
>> res@mpMaxLonF = maxlon
>>
>> ;******************************************************
>> ; Plot wind barb
>> ;******************************************************
>>
>> plot=gsn_csm_vector_map_ce(wks,U(653,3,:,:),V(653,3,:,:),res)
>>
>> end
>>
>>
>> I want to plot winds at 2002 june....so converted time using
>> *ut_calenda*r function and i got it is :653 and level is 850 hpa -->3
>> thus U(653,3,:,:) and V(653,3,:,:). I hope the calculation is correct.
>>
>> The error am getting is:
>>
>>
>> fatal:VectorPlotDraw: VVECTR - VECTOR NDC LENGTH TOO GREAT
>> fatal:VectorPlotDraw: error drawing vectors
>> fatal:VectorPlotDraw: draw error
>> fatal:PlotManagerDraw: error in plot draw
>> fatal:_NhlPlotManagerDraw: Draw error
>>
>>
>>
>> Thanks in advance
>>
>>
>> --
>> *********************************************************************
>> A.R.Ragi
>> M.Tech Atmospheric science
>> Department of Atmospheric science
>> Cochin University of Science and Technology
>> Email : ar.ragi@gmail.com <mailto:ar.ragi@gmail.com>
>>
>> ************************************************************************
>> "I want to know how God created this world.I am not interested in this
>> or that phenomenon. I want to know, his thought, the rest are details"
>> . ---Albert Einstein
>>
>> ************************************************************************
>>
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-- 
__________________________________________________
Adam Phillips 
asphilli@ucar.edu
National Center for Atmospheric Research   tel: (303) 497-1726
Climate and Global Dynamics Division         fax: (303) 497-1333
P.O. Box 3000				
Boulder, CO 80307-3000    http://www.cgd.ucar.edu/cas/asphilli
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